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How do you write a migration to rename an ActiveRecord model and its table in Rails?
...y.
Edit:
In Rails 3.1 & 4, ActiveRecord::Migration::CommandRecorder knows how to reverse rename_table migrations, so you can do this:
class RenameOldTableToNewTable < ActiveRecord::Migration
def change
rename_table :old_table_name, :new_table_name
end
end
(You still have to go t...
Why do I get AttributeError: 'NoneType' object has no attribute 'something'?
...The sort() method of a list sorts the list in-place, that is, mylist is modified. But the actual return value of the method is None and not the list sorted. So you've just assigned None to mylist. If you next try to do, say, mylist.append(1) Python will give you this error.
...
PHP script to loop through all of the files in a directory?
...ike to be able to sort the files by name, type or by date created/added/modified. (Think fancy directory "index".) I'd also like to be able to add exclusions to the list of files, such as the script itself or other "system" files. (Like the . and .. "directories".)
...
How to write DataFrame to postgres table?
...s 0.14 (released end of May 2014), postgresql is supported. The sql module now uses sqlalchemy to support different database flavors. You can pass a sqlalchemy engine for a postgresql database (see docs). E.g.:
from sqlalchemy import create_engine
engine = create_engine('postgresql://scott:tiger@lo...
How to repeat a “block” in a django template
...nd this seems like a good approach. thanks.
– thebiglife
Sep 27 '09 at 19:17
1
This approach is e...
How to get GET (query string) variables in Express.js on Node.js?
...
What additional/better functionality does hapi provide ( if any ) ?
– BaltoStar
Aug 5 '13 at 18:44
182
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Image Greyscale with CSS & re-color on mouse-over?
...
If said images need to be linked to other website tho, how could this be done if the images are set as backgrounds?
– Meta
Sep 1 '11 at 17:39
...
Difference between DirectCast() and CType() in VB.NET
...ld with a C# (int) cast. But you can cast from an IEnumerable to an array, if your underlying IEnumerable object variable really is an Array. And of course you can cast from Object to anything, assuming the type of your object instance really is somewhere below your cast type in the inheritance tree...
How to loop backwards in python? [duplicate]
...
range() and xrange() take a third parameter that specifies a step. So you can do the following.
range(10, 0, -1)
Which gives
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
But for iteration, you should really be using xrange instead. So,
xrange(10, 0, -1)
Note for Python 3 users:...
Is there a RegExp.escape function in Javascript?
...
If you are going to use this function in a loop, it's probably best to make the RegExp object it's own variable var e = /[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g; and then your function is return s.replace(e, '\\$&'); This wa...